The present disclose pertains to a device for destacking books, brochures, book blocks or similar cubic printed products.
Destacking devices are used for separating stacked products such as books, brochures, book blocks or the like and delivering said products to a processing machine.
Known book block feeders feature a stacking tunnel for accommodating book blocks that are delivered individually or in stacks from a reservoir, e.g., an accumulating roller conveyor, wherein the stacking tunnel features an intermediate feeder in the form of supports that are oriented in the delivery direction and can be laterally moved out of the stacking tunnel in order to vertically set down the book blocks. The respective bottom book block in the stacking tunnel is pushed forward and transferred from a delivery conveyor to the infeed conveyor of the next machine. The systems are complicated and the infeed and the delivery of the book blocks inherently take place at different heights.
A destacking device of this type in the form of a book block feeder with constant infeed and delivery height is known from DE 198 11 635 A1, wherein the book block feeder comprises an endless separating belt with a non-skid surface that is powered by a frequency-controlled drive and successively receives the book block stacks, lateral boundaries for the book block stacks and a height-adjustable retaining element that forms a passage for the respective bottom book block to be separated. The retaining element can be inclined in the transport direction in order to appropriately alleviate the load on the book block to be separated and thusly improve the functional reliability during the separation.
The infeed of the separating belt is provided with a support plate for supporting the rear edge of the book block lying on the bottom book block relative to the separating belt while the bottom book block is pulled out. The aforementioned retaining element can be positioned relative to the separating belt in accordance with the format length of the book block. A feeding belt driven in a cyclic fashion is also assigned to the separating belt in order to deliver the next stack as far as the retaining element situated in the separating position of the separating belt.
The destacking device disclosed in DE 198 11 635 A1 makes it possible to quickly and easily destack book block stacks. However, when processing thick book blocks with a small format, the residual stack lying on the bottom book block may fall over rearward when the bottom book block is pulled out of a high stack.